What are/is side effects of hysterectomy operation?

Broad question. There are surgical risks with any procedure - ie. Bleeding, infection, damage to adjacent organs, failure to cure, etc. There are also usually benefits for the majority of procedures performed. In the case of hysterectomy - we expect resolution of whatever problem prompted the surgery. The specific side effects of hysterectomy include - no more periods, no uterine prolapse, fewer cramps, etc.